* {
    margin: 0;
    padding: 0;
}

ul,
ol,
li {
    list-style: none;
}

.box {
    width: 600px;
    height: 400px;
    border: 10px solid #333;
    margin: 30px auto;
    display: flex;
    flex-direction: column;
}

.box>ul {
    width: 100%;
    height: 40px;
    display: flex;
}

.box>ul>li {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 30px;
    color: #fff;
    background-color: hotpink;
}

.box>ul>li.active {
    background-color: orange;
}

.box>ol {
    flex: 1;
    position: relative;
}

.box>ol>li {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    background-color: skyblue;
    color: #fff;
    font-size: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
    display: none;
}

.box>ol>li.active {
    display: flex;
}